Field of the Invention
The present invention relates to a pneumatic tire which can discharge a static electricity generated in a vehicle body and a tire to a road surface.
Description of the Related Art
In recent years, for the purpose of reducing a rolling resistance of a tire which has a strong relationship with a fuel consumption performance, there has been proposed a pneumatic tire in which a rubber member such as a tread rubber or the like is formed by a nonconductive rubber in which a silica is blended at a high rate. However, since the rubber member mentioned above is high in an electric resistance in comparison with a conventional product in which a carbon black is blended at a high rate, and inhibits a discharge of a static electricity which is generated in a vehicle body or a tire to a road surface, there is a problem that a defect such as a radio noise or the like tends to be generated.
Accordingly, there has been developed a pneumatic tire structured such that an exciting performance can be achieved by providing a conductive rubber in which a carbon black or the like is blended, while forming a tread rubber by a nonconductive rubber. For example, in a pneumatic tire described in patent document 1 (JP-A-2009-161070), there is disclosed a tire in which a conductive route for discharging a static electricity is constructed by making a conductive rubber extend to a side surface of a bottom surface from a ground surface of a tread rubber through an inner portion of the tread rubber which is formed by a nonconductive rubber. Further, a tire in which a conductive route is formed in the same manner as mentioned above is disclosed in patent document 2 (JP-A-2010-115935).